Windows 7 lifecycle fact sheet
Windows 7 SP1 mainstream support ended on January 13, 2015. Mainstream Support for Business, Developer, and Desktop Operating Systems will be provided for 5 years or for 2 years after the successor product (N+1) is released, whichever is longer. Microsoft will also provide Extended Support for the 5 years following Mainstream support or for 2 years after the second successor product (N+2) is released, whichever is longer. Finally, most Business, Developer, and Desktop Operating System Software products will receive at least 10 years of online self-help support.
Be sure to install Windows 7 Service Pack 1 now to continue to receive support and updates.
Read more here - http://windows.microsoft.com/en-us/windows/lifecycle